> I am looking for a code generator which can generate 80x86 assembly> code from an IR

In our MOCKA (Karlsruhe Modula-2 Compiler) environment we use
an IR called MOBIL developed at the GMD
(ftp://i44ftp.info.uni-karlsruhe.de/pub/papers/vollmer/mobil.ps.gz),
which is very suitable for classical languages like Modula, Pascal
and C, optimizers are available.
Backends exist for several architectures (68k, SPARC, MIPS,
PowerPC and Intel) and are generated with the backend-generator-
generator BEG
(ftp://i44ftp.info.uni-karlsruhe.de/pub/papers/emmel/begmanual.ps).
This generator tool has gone commercial, but you can obtain
an older version for free. Of course one could talk about
the generated backend for Intel processors (C-source)...